//
//  main.cpp
//  hw4_17 PI近似值
//
//  Created by baili on 2024/5/18.
//

#include <iostream>

int main() {
    int sum = 0;
    int sign = 1;
    for (int i = 1; i <= 101; i += 2) {
        sum += sign * i;
        sign = -sign;
    }
    std::cout << "结果: " << sum << std::endl;
    return 0;
}
